Orbital magnetic moment and extrinsic spin Hall effect for iron impurity in gold

TL;DR

This study combines electronic structure calculations and impurity modeling to analyze the magnetic properties of iron in gold and its impact on the spin Hall effect, finding no significant extrinsic effect.

Contribution

It demonstrates that the LDA+U method accurately reproduces experimental XMCD data and estimates a small spin Hall angle, indicating limited extrinsic spin Hall effect from iron impurities.

Findings

LDA+U reproduces XMCD data well

No large orbital moment on Fe atom

Spin Hall angle estimated at ~0.025

Abstract

We report electronic structure calculations of an iron impurity in gold host. The spin, orbital and dipole magnetic moments were investigated using the LDA+$U$ correlated band theory. We show that the {\em around-mean-field}-LDA+$U$ reproduces the XMCD experimental data well and does not lead to formation of a large orbital moment on the Fe atom. Furthermore, exact diagonalization of the multi-orbital Anderson impurity model with the full Coulomb interaction matrix and the spin-orbit coupling is performed in order to estimate the spin Hall angle. The obtained value $\gamma_S \approx 0.025$ suggests that there is no giant extrinsic spin Hall effect due to scattering on iron impurities in gold.